In a head-on-collision, the torso and the head of an occupant are displaced forward until the forward movement is limited by the restraining belt. In the following rebound, the occupant's torso and head strike the squab and the headrest, respectively. In a conventional restraining system, the impact velocity is diminished because the squab is caused to follow up the forward motion of the occupant by a pyrotechnical drive with the result that the distances of the torso from the squab and also of the head from the headrest are reduced. Thereby, the risk of injury in the cervical vertebral region can be diminished. Furthermore, a restraining system is known which is adapted to increase the angle of inclination of the seat area, i.e. the surface of the cushion on which the occupant seats. In the case of short vehicle occupants there is in fact the danger that, in a vehicle impact, they may be so deeply thrust into the cushion of the vehicle seat owing to their low center of gravity in conjunction with a badly fitting restraining belt that the restraining belt slips onto the abdomen of the occupant where it may cause serious injuries. The danger of injury is even further increased, if the transfer of momentum is obliquely from the front, since then the pelvis of the occupant additionally rotates. By adjustment of the angle of slant of the seat area, the position of the occupant is stabilized so that he or she is now unable to be so deeply thrust into the cushion.